US4131081A - Toner concentration detecting apparatus - Google Patents

Toner concentration detecting apparatus Download PDF

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Publication number
US4131081A
US4131081A US05/783,554 US78355477A US4131081A US 4131081 A US4131081 A US 4131081A US 78355477 A US78355477 A US 78355477A US 4131081 A US4131081 A US 4131081A
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US
United States
Prior art keywords
developing powder
hollow body
magnetic
toner concentration
developing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/783,554
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English (en)
Inventor
Isamu Terashima
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Hitachi Ltd
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Hitachi Ltd
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Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
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Publication of US4131081A publication Critical patent/US4131081A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0848—Arrangements for testing or measuring developer properties or quality, e.g. charge, size, flowability
    • G03G15/0849—Detection or control means for the developer concentration
    • G03G15/0853—Detection or control means for the developer concentration the concentration being measured by magnetic means

Definitions

  • the present invention relates to an apparatus for detecting a toner concentration (composition ratio) in developing powder in an electrostatic printing machine which uses the developing powder comprising a mixture of magnetic carrier and toner.
  • the developing powder in transporting the developing powder to a magnetically responsive device, the developing powder is magnetized into chain at downstream of the magnetically responsive device to facilitate the transport, and the magnetization of the developing powder is released in an active region of the magnetically responsive device for preventing external magnetic flux from acting on the magnetically responsive device.
  • FIG. 1 is a longitudinal sectional view of major sections of a developing apparatus incorporating detecting apparatus of the present invention.
  • FIG. 2 shows a perspective and longitudinal sectional view of major sections of said developing apparatus with developing powder being removed.
  • FIG. 3 shows an electric circuit including the detection coil for indicating a detected concentration.
  • numeral I denotes a photosensitive drum, on a surface of which a electrostatic latent image is formed by a well-known electronic photography technology.
  • Numeral II denotes a developing apparatus which uses developing powder and which incorporates a toner concentration detecting apparatus III of the present invention.
  • the developing apparatus II has a pair of side plates 1 and a case 2 which define a chamber to receive developing powder 7 at the bottom portion thereof.
  • the developing powder 7 includes powdered magnetic carrier and toner.
  • Numeral 3 denotes a permanent magnet roll or bar supported between the pair of side plates 1 and is circumferentially magnetized.
  • Numeral 4 denotes a sleeve of non-magnetic material arranged concentrically to the permanent magnet 3 and rotatably supported.
  • Numerals 5 and 6 denote blending screws for blending or agitating the developing powder 7 and rotatably supported between the pair of side plates 1.
  • the photosensitive drum I, sleeve 4 and the blending screws 5 and 6 are linked by an external driving mechanism, not shown, such that they are synchronously driven.
  • numeral 8 denotes a developing powder guide plate made of non-magnetic material, and end of which is arranged to face the outer periphery of the sleeve 4 with a slight clearance therebetween to divert a portion of the developing powder transported along the outer periphry of the sleeve 4.
  • Numeral 9 denotes a cover formed at the rear of the developing powder guide plate 8 to maintain the amount of the developing powder transported over the guide plate 8 to a fixed amount.
  • Numeral 10a denotes a detection coil wound on a hollow bobbin 10b which is mounted on the underside of the guide plate 8 such that an aperture 8a formed at a rear end of the guide plate 8 aligns to an aperture 10c of the bobbin 10b.
  • the bobbin 10b is made of non-magnetic material and a projection of the center aperture 10c is of rectangular shape.
  • Numeral 11 denotes a magnetic bypass plate of magnetic material having an L-shape, one leg of which is mounted on the underside of the guide plate 8 near the entry of the cover 9 and the other leg of which depends parallely with the bobbin 10b and extends near the top of the magnetic powder 7 at the bottom of the chamber.
  • Numeral 12 denotes a baffle board for directing the flow of the developing powder from the bobbin 10b into the sleeve 4 and the blending screw 6 and it is made of non-magnetic material. Those elements are integrally coupled and the entire assembly is mounted in the case 2 by the baffle board 12.
  • Numeral 13 denotes a restricting plate for restricting the thickness of the developing powder layer transported by the sleeve 4 by being deposited thereon by magnetic attraction force of the magnet 3, to a fixed thickness such that the outer surface of the developing powder layer slightly rubs the surface of the photosensitive drum I.
  • Numeral 14 denotes a cover for preventing the scatter of the developing powder 7 and it is pivotably mounted.
  • the developing powder layer As the sleeve 4 rotates in the direction of the arrow B, the developing powder layer also moves in the same direction so that the outer periphery of the layer contacts the photosensitive drum I to develop a latent image thereof. Thereafter, when the developing powder layer reaches immediately above the magnet pole S 1 , it is partially deverted from the surface of the sleeve 4 by the guide plate 8 and the diverted developing powder is transported on the guide plate 8 toward the cover 9.
  • the line of magnetic force 3d between the magnet poles S 1 and N 2 primarily passes from the magnet pole N 2 through the developing powder 7 at the bottom of the chamber, the bypass plate 11, the developing powder 7 on the guide plate 8 to the magnet pole S 1 , and does not pass through the aperture 10c of the bobbin 10b.
  • the developing powder 7 in the area from the surface of the sleeve to the vicinity of the entrance of the cover 9 is magnetized into chain so that the developing powder on the guide plate is pushed by that on the sleeve to facilitate smooth transport of the developing powder to the cover.
  • the magnetic powder 7 which has entered in the cover 9 is released from magnetic binding and the attraction forces among the magnetic carriers are substantially nullified.
  • the developing powder 7 flows down through the center aperture 10c of the bobbin 10b in a free state.
  • the developing powder 7 passed through the aperture 10c is baffled by the baffle plate 12 located near the aperture 10c and again magnetized into chain by the magnetic flux passing through the bypass plate 11 and passed toward the magnet pole N 2 .
  • the stream of the developing powder 7 within the bobbin 10b is stabilized and the variation of the developing powder density within the bobbin is minimized.
  • the action of the external magnetic flux to the coil 10a is prevented.
  • the coil 10a wound on the bobbin 10b exhibits an inductance determined by a permeability of the developing powder 7 flowing through the aperture 10c.
  • a series circuit of the coil 10a and a capacitor 16 is connected across output terminals of a constant frequency oscillator 15 (of the order of 100 KHz), and a voltage across the coil 10a is rectified by a diode 17 and filtered by a capacitor 18.
  • a difference between a voltage across the capacitor 18 and a reference voltage across a potentiometer 20 is indicated by a meter 19 to indicate a detected concentration of the developing powder 7 relative to a reference concentration.
  • the constants of the capacitor 16 and the coil 10a are selected such that a resonance frequency thereof is slightly staggered from the output frequency of the oscillator 15 when the toner concentration is at the reference value, so that a large change in the inductance of the coil (i.e. voltage across the coil) is produced by the reduction of the toner concentration of the developing powder.
  • the detection coil may be replaced by a magnetically responsive semiconductor device.
  • magnetic flux is caused to pass from a reference magnet to the developing powder flowing through the aperture 10c of the bobbin 10a and a change of magnetic flux due to reluctance change is utilized.
  • the guide plate 8 need not divert the developing powder 7 over the entire axial width of the sleeve 4 but it may sample the developing powder 7 from a portion of the area of the developing powder actually used for the development of latent image.
  • a larger axial dimension of the layer of the developing powder 7 passing through the detection coil 10a is advantageous in preventing the offset of the detection.
  • the indication meter 19 may be replaced by a solenoid valve to automatically supply toner to the developing powder.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Electrochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Dry Development In Electrophotography (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
US05/783,554 1976-04-14 1977-04-01 Toner concentration detecting apparatus Expired - Lifetime US4131081A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP4135276A JPS52125339A (en) 1976-04-14 1976-04-14 Detector for toner density
JP51-41352 1976-04-14

Publications (1)

Publication Number Publication Date
US4131081A true US4131081A (en) 1978-12-26

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ID=12606106

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/783,554 Expired - Lifetime US4131081A (en) 1976-04-14 1977-04-01 Toner concentration detecting apparatus

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US (1) US4131081A (en, 2012)
JP (1) JPS52125339A (en, 2012)
DE (1) DE2716408C2 (en, 2012)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2942066A1 (de) * 1978-10-18 1980-04-24 Hitachi Ltd Tonerkonzentrations-erfassungseinrichtung
US4240375A (en) * 1977-04-13 1980-12-23 Hitachi, Ltd. Apparatus for detecting concentration of toner in developing powder
US4243059A (en) * 1977-06-10 1981-01-06 Basf Aktiengesellschaft Method and device for determining the homogeneity of magnetic dispersions
EP0029584A1 (en) * 1979-11-26 1981-06-03 Hitachi, Ltd. Method for operating electrophotographic copying apparatus
EP0029710A1 (en) * 1979-11-24 1981-06-03 Hitachi, Ltd. Toner concentration detecting apparatus
EP0044752A3 (en) * 1980-07-23 1982-02-10 Mita Industrial Co. Ltd. Dual component developing material detecting device for electrostatic copying apparatus
US4405226A (en) * 1980-07-23 1983-09-20 Mita Industrial Company Limited Developing material supplying control device for electrostatic copying apparatus
EP0137141A1 (en) * 1983-08-12 1985-04-17 Hitachi, Ltd. Toner Concentration Detecting Apparatus
EP0161795A1 (en) * 1984-05-16 1985-11-21 Mita Industrial Co. Ltd. Developing apparatus
US6342273B1 (en) 1994-11-16 2002-01-29 Dsm N.V. Process for coating a substrate with a powder paint composition
US20100290795A1 (en) * 2009-05-15 2010-11-18 Konica Minolta Business Technologies, Inc. Toner concentration sensor and toner concentration control method
US20140016977A1 (en) * 2012-07-10 2014-01-16 Canon Kabushiki Kaisha Developer accommodating container and image forming apparatus

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54102128A (en) * 1978-01-27 1979-08-11 Kopia Kk Device for developing with developer density measuring instrument
JPS54115246A (en) * 1978-02-28 1979-09-07 Ricoh Co Ltd Toner concentration detector
JPS6031408U (ja) * 1983-08-10 1985-03-04 日本電気株式会社 通信機用シエルタ−

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3527651A (en) * 1966-10-20 1970-09-08 Addressograph Multigraph Method of and apparatus for developing electrostatic images
US3572551A (en) * 1969-03-27 1971-03-30 Rca Corp Apparatus for monitoring and controlling the concentration of toner in a developer mix
US3698926A (en) * 1969-11-11 1972-10-17 Katsuragawa Denki Kk Method and apparatus for supplementing toner in electrophotographic machines
US3802381A (en) * 1968-07-30 1974-04-09 Continental Can Co Apparatus for measuring concentration ratios of a mixture of materials
US3835380A (en) * 1973-08-14 1974-09-10 Xerox Corp Electrometer system
US3892672A (en) * 1970-08-21 1975-07-01 Addressograph Multigraph Automatic toner concentrate detector and control device
US3911864A (en) * 1973-01-17 1975-10-14 Xerox Corp Toner preloaded magnetic brush development system
US3999687A (en) * 1974-07-17 1976-12-28 Savin Business Machines Corporation Toner concentration detector

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970036A (en) * 1974-07-17 1976-07-20 Savin Business Machines Corporation Toner concentration detector for dry powder magnetic brush toning system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3527651A (en) * 1966-10-20 1970-09-08 Addressograph Multigraph Method of and apparatus for developing electrostatic images
US3802381A (en) * 1968-07-30 1974-04-09 Continental Can Co Apparatus for measuring concentration ratios of a mixture of materials
US3572551A (en) * 1969-03-27 1971-03-30 Rca Corp Apparatus for monitoring and controlling the concentration of toner in a developer mix
US3698926A (en) * 1969-11-11 1972-10-17 Katsuragawa Denki Kk Method and apparatus for supplementing toner in electrophotographic machines
US3892672A (en) * 1970-08-21 1975-07-01 Addressograph Multigraph Automatic toner concentrate detector and control device
US3911864A (en) * 1973-01-17 1975-10-14 Xerox Corp Toner preloaded magnetic brush development system
US3835380A (en) * 1973-08-14 1974-09-10 Xerox Corp Electrometer system
US3999687A (en) * 1974-07-17 1976-12-28 Savin Business Machines Corporation Toner concentration detector

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4240375A (en) * 1977-04-13 1980-12-23 Hitachi, Ltd. Apparatus for detecting concentration of toner in developing powder
US4243059A (en) * 1977-06-10 1981-01-06 Basf Aktiengesellschaft Method and device for determining the homogeneity of magnetic dispersions
US4292925A (en) * 1978-10-18 1981-10-06 Hitachi, Ltd. Toner concentration detecting apparatus
DE2942066A1 (de) * 1978-10-18 1980-04-24 Hitachi Ltd Tonerkonzentrations-erfassungseinrichtung
US4342283A (en) * 1979-11-24 1982-08-03 Hitachi, Ltd. Developing apparatus for electrostatic duplicator
EP0029710A1 (en) * 1979-11-24 1981-06-03 Hitachi, Ltd. Toner concentration detecting apparatus
EP0029584A1 (en) * 1979-11-26 1981-06-03 Hitachi, Ltd. Method for operating electrophotographic copying apparatus
US4405226A (en) * 1980-07-23 1983-09-20 Mita Industrial Company Limited Developing material supplying control device for electrostatic copying apparatus
EP0044752A3 (en) * 1980-07-23 1982-02-10 Mita Industrial Co. Ltd. Dual component developing material detecting device for electrostatic copying apparatus
EP0137141A1 (en) * 1983-08-12 1985-04-17 Hitachi, Ltd. Toner Concentration Detecting Apparatus
EP0161795A1 (en) * 1984-05-16 1985-11-21 Mita Industrial Co. Ltd. Developing apparatus
US6342273B1 (en) 1994-11-16 2002-01-29 Dsm N.V. Process for coating a substrate with a powder paint composition
US20100290795A1 (en) * 2009-05-15 2010-11-18 Konica Minolta Business Technologies, Inc. Toner concentration sensor and toner concentration control method
US8380092B2 (en) * 2009-05-15 2013-02-19 Konica Minolta Business Technologies, Inc. Toner concentration sensor and toner concentration control method
US20140016977A1 (en) * 2012-07-10 2014-01-16 Canon Kabushiki Kaisha Developer accommodating container and image forming apparatus
US9423760B2 (en) * 2012-07-10 2016-08-23 Canon Kabushiki Kaisha Developer accommodating container and image forming apparatus

Also Published As

Publication number Publication date
JPS5547744B2 (en, 2012) 1980-12-02
DE2716408C2 (de) 1984-05-10
JPS52125339A (en) 1977-10-21
DE2716408A1 (de) 1977-10-27

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